On Wed, 28 Oct 2020 00:57:41 -0500 Lijun Pan wrote:

We need to notify peers only when failover and migration happen.
It is unnecessary to call that in other events like
FATAL, NON_FATAL, CHANGE_PARAM, and TIMEOUT resets
since in those scenarios the MAC address and ip address mapping
does not change. Originally all the resets except CHANGE_PARAM
are processed by do_reset such that we need to find out
failover and migration cases in do_reset and call notifier functions.
We only need to notify peers in do_reset and do_hard_reset.
We don't need notify peers in do_change_param_reset since it is
a CHANGE_PARAM reset. In a nested reset case, it will finally
call into do_hard_reset with reasons other than failvoer and
migration. So, we don't need to check the reset reason in
do_hard_reset and just call notifier functions anyway.

You're completely undoing the commit you linked to:

commit 61d3e1d9bc2a1910d773cbf4ed6f587a7a6166b5
Author: Nathan Fontenot [off-list ref]
Date:   Mon Jun 12 20:47:45 2017 -0400

    ibmvnic: Remove netdev notify for failover resets
    
    When handling a driver reset due to a failover of the backing
    server on the vios, doing the netdev_notify_peers() can cause
    network traffic to stall or halt. Remove the netdev notify call
    for failover resets.
    
    Signed-off-by: Nathan Fontenot [off-list ref]
    Signed-off-by: David S. Miller [off-list ref]

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index fd3ef3005fb0..59ea7a5ae776 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c

@@ -1364,7 +1364,9 @@ static int do_reset(struct ibmvnic_adapter *adapter,
        for (i = 0; i < adapter->req_rx_queues; i++)
                napi_schedule(&adapter->napi[i]);
 
-       netdev_notify_peers(netdev);
+       if (adapter->reset_reason != VNIC_RESET_FAILOVER)
+               netdev_notify_peers(netdev);
+
        return 0;
 }

But you don't seem to address why this change was unnecessary.

AFAIK you're saying "we only need this event for FAILOVER and MOBILITY"
but the previous commit _excluded_ FAILOVER for some vague reason.

If the previous commit was incorrect you need to explain that in the
commit message.

netdev_notify_peers calls below two functions with rtnl lock().
	call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
	call_netdevice_notifiers(NETDEV_RESEND_IGMP, dev);
When netdev_notify_peers was substituted in
commit 986103e7920c ("net/ibmvnic: Fix RTNL deadlock during device reset"),
call_netdevice_notifiers(NETDEV_RESEND_IGMP, dev) was missed.

That should be a separate patch.

Fixes: 61d3e1d9bc2a ("ibmvnic: Remove netdev notify for failover resets")
Fixes: 986103e7920c ("net/ibmvnic: Fix RTNL deadlock during device
reset")

Please don't line-wrap fixes tags.